Watson claims he is fit to bat and bowl at Perth

Australia's Shane Watson has declared himself fit for both batting and bowling duties in the third and final test against South Africa beginning in Perth on Friday.

The all-rounder missed the first two drawn tests of the series in Brisbane and Adelaide with a calf injury but was named in the squad for the final match.

"Over the last week I have gradually built up my bowling and my running," he told reporters on Wednesday.

"I am up to bowling as many overs as Michael (Clarke) wants, the normal workload I have in a test."

The 31-year-old was deemed fit to play as a specialist batsman in the second test but Australia opted to give him a chance to regain full fitness.

"The decision to miss the last test was a good one in hindsight because it gave me the best chance to bowl well here," he said.

"I understand (bowling a lot of overs) could be a possibility for me ... but in the end my body is in the condition to do it.

"I'm certainly fresh compared to some of the other guys who have been out there, so my body should be right."

Australia need a victory at the WACA to return to the number one spot after a gap of more than three years, while a third draw would keep South Africa as the world's top side in the longest form of the game.